samd: Add a vref=num option to the ADC and DAC constructor.
ADC: The argument of vref=num is an integer. Values for num are:
SAMD21:
0 INT1V 1.0V voltage reference
1 INTVCC0 1/1.48 Analog voltage supply
2 INTVCC1 1/2 Analog voltage supply (only for VDDANA > 2.0V)
3 VREFA External reference
4 VREFB External reference
SAMD51:
0 INTREF internal bandgap reference
1 INTVCC1 Analog voltage supply
2 INTVCC0 1/2 Analog voltage supply (only for VDDANA > 2.0v)
3 AREFA External reference A
4 AREFB External reference B
5 AREFC External reference C (ADC1 only)
DAC: The argument of vref=num is an integer. Suitable values:
SAMD21:
0 INT1V Internal voltage reference
1 VDDANA Analog voltage supply
2 VREFA External reference
SAMD51:
0 INTREF Internal bandgap reference
1 VDDANA Analog voltage supply
2 VREFAU Unbuffered external voltage reference (not buffered in DAC)
4 VREFAB Buffered external voltage reference (buffered in DAC).
This commit is contained in:
robert-hh
Damien George
parent
a73dcb3d22
commit
e69313f89c
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@ -254,16 +254,38 @@ an external ADC.
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ADC Constructor
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```````````````
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.. class:: ADC(dest, *, average=16)
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.. class:: ADC(dest, *, average=16, vref=n)
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:noindex:
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Construct and return a new ADC object using the following parameters:
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Construct and return a new ADC object using the following parameters:
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- *dest* is the Pin object on which the ADC is output.
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- *dest* is the Pin object on which the ADC is output.
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Keyword arguments:
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Keyword arguments:
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- *average* is used to reduce the noise. With a value of 16 the LSB noise is about 1 digit.
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- *average* is used to reduce the noise. With a value of 16 the LSB noise is about 1 digit.
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- *vref* sets the reference voltage for the ADC.
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The default setting is for 3.3V. Other values are:
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==== ============================== ===============================
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vref SAMD21 SAMD51
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==== ============================== ===============================
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0 1.0V voltage reference internal bandgap reference (1V)
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1 1/1.48 Analogue voltage supply Analogue voltage supply
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2 1/2 Analogue voltage supply 1/2 Analogue voltage supply
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3 External reference A External reference A
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4 External reference B External reference B
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5 - External reference C
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==== ============================== ===============================
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ADC Methods
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```````````
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.. method:: read_u16()
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Read a single ADC value as unsigned 16 bit quantity. The voltage range is defined
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by the vref option of the constructor, the resolutions by the bits option.
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DAC (digital to analog conversion)
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----------------------------------
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@ -280,6 +302,32 @@ The DAC class provides a fast digital to analog conversion. Usage example::
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The resolution of the DAC is 12 bit for SAMD51 and 10 bit for SAMD21. SAMD21 devices
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have 1 DAC channel at GPIO PA02, SAMD51 devices have 2 DAC channels at GPIO PA02 and PA05.
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DAC Constructor
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```````````````
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.. class:: DAC(id, *, vref=3)
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:noindex:
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The vref arguments defines the output voltage range, the callback option is used for
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dac_timed(). Suitable values for vref are:
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==== ============================ ================================
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vref SAMD21 SAMD51
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==== ============================ ================================
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0 Internal voltage reference Internal bandgap reference (~1V)
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1 Analogue voltage supply Analogue voltage supply
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2 External reference Unbuffered external reference
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3 - Buffered external reference
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==== ============================ ================================
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DAC Methods
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```````````
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.. method:: write(value)
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Write a single value to the selected DAC output. The value range is 0-1023 for
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SAMD21 and 0-4095 for SAMD51. The voltage range depends on the vref setting.
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Software SPI bus
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----------------
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@ -2,3 +2,4 @@
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#define MICROPY_HW_MCU_NAME "SAMD21G18A"
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#define MICROPY_HW_XOSC32K (1)
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#define MICROPY_HW_ADC_VREF (2)
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@ -40,11 +40,40 @@ typedef struct _machine_adc_obj_t {
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uint8_t id;
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uint8_t avg;
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uint8_t bits;
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uint8_t vref;
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} machine_adc_obj_t;
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#define DEFAULT_ADC_BITS 12
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#define DEFAULT_ADC_AVG 16
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#if defined(MCU_SAMD21)
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static uint8_t adc_vref_table[] = {
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ADC_REFCTRL_REFSEL_INT1V_Val, ADC_REFCTRL_REFSEL_INTVCC0_Val,
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ADC_REFCTRL_REFSEL_INTVCC1_Val, ADC_REFCTRL_REFSEL_AREFA_Val, ADC_REFCTRL_REFSEL_AREFB_Val
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};
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#if MICROPY_HW_ADC_VREF
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#define DEFAULT_ADC_VREF MICROPY_HW_ADC_VREF
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#else
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#define DEFAULT_ADC_VREF (3)
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#endif
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#define ADC_EVSYS_CHANNEL 0
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#elif defined(MCU_SAMD51)
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static uint8_t adc_vref_table[] = {
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ADC_REFCTRL_REFSEL_INTREF_Val, ADC_REFCTRL_REFSEL_INTVCC1_Val,
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ADC_REFCTRL_REFSEL_INTVCC0_Val, ADC_REFCTRL_REFSEL_AREFA_Val,
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ADC_REFCTRL_REFSEL_AREFB_Val, ADC_REFCTRL_REFSEL_AREFC_Val
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};
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#if MICROPY_HW_ADC_VREF
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#define DEFAULT_ADC_VREF MICROPY_HW_ADC_VREF
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#else
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#define DEFAULT_ADC_VREF (3)
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#endif
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#endif // defined(MCU_SAMD21)
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Adc *const adc_bases[] = ADC_INSTS;
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uint32_t busy_flags = 0;
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bool init_flags[2] = {false, false};
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@ -66,17 +95,18 @@ STATIC void adc_obj_print(const mp_print_t *print, mp_obj_t o, mp_print_kind_t k
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(void)kind;
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machine_adc_obj_t *self = MP_OBJ_TO_PTR(o);
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mp_printf(print, "ADC(%s, device=%u, channel=%u, bits=%u, average=%u)",
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mp_printf(print, "ADC(%s, device=%u, channel=%u, bits=%u, average=%u, vref=%d)",
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pin_name(self->id), self->adc_config.device,
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self->adc_config.channel, self->bits, 1 << self->avg);
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self->adc_config.channel, self->bits, 1 << self->avg, self->vref);
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}
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STATIC mp_obj_t adc_obj_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
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enum { ARG_id, ARG_bits, ARG_average };
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enum { ARG_id, ARG_bits, ARG_average, ARG_vref };
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static const mp_arg_t allowed_args[] = {
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{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_OBJ },
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{ MP_QSTR_bits, MP_ARG_INT, {.u_int = DEFAULT_ADC_BITS} },
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{ MP_QSTR_average, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_ADC_AVG} },
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{ MP_QSTR_vref, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_ADC_VREF} },
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};
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// Parse the arguments.
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@ -99,8 +129,14 @@ STATIC mp_obj_t adc_obj_make_new(const mp_obj_type_t *type, size_t n_args, size_
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uint32_t avg = log2i(args[ARG_average].u_int);
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self->avg = (avg <= 10 ? avg : 10);
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uint8_t vref = args[ARG_vref].u_int;
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if (0 <= vref && vref < sizeof(adc_vref_table)) {
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self->vref = vref;
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}
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// flag the device/channel as being in use.
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busy_flags |= (1 << (self->adc_config.device * 16 + self->adc_config.channel));
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init_flags[self->adc_config.device] = false;
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adc_init(self);
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@ -111,6 +147,8 @@ STATIC mp_obj_t adc_obj_make_new(const mp_obj_type_t *type, size_t n_args, size_
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STATIC mp_obj_t machine_adc_read_u16(mp_obj_t self_in) {
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machine_adc_obj_t *self = MP_OBJ_TO_PTR(self_in);
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Adc *adc = adc_bases[self->adc_config.device];
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// Set the reference voltage. Default: external AREFA.
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adc->REFCTRL.reg = adc_vref_table[self->vref];
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// Set Input channel and resolution
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// Select the pin as positive input and gnd as negative input reference, non-diff mode by default
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adc->INPUTCTRL.reg = ADC_INPUTCTRL_MUXNEG_GND | self->adc_config.channel;
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@ -183,7 +221,7 @@ static void adc_init(machine_adc_obj_t *self) {
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// Divide 48MHz clock by 32 to obtain 1.5 MHz clock to adc
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adc->CTRLB.reg = ADC_CTRLB_PRESCALER_DIV32;
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// Select external AREFA as reference voltage.
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adc->REFCTRL.reg = ADC_REFCTRL_REFSEL_AREFA;
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adc->REFCTRL.reg = adc_vref_table[self->vref];
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// Average: Accumulate samples and scale them down accordingly
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adc->AVGCTRL.reg = self->avg | ADC_AVGCTRL_ADJRES(self->avg);
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// Enable ADC and wait to be ready
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@ -222,8 +260,8 @@ static void adc_init(machine_adc_obj_t *self) {
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adc->CALIB.reg = ADC_CALIB_BIASCOMP(biascomp) | ADC_CALIB_BIASR2R(biasr2r) | ADC_CALIB_BIASREFBUF(biasrefbuf);
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// Divide 48MHz clock by 32 to obtain 1.5 MHz clock to adc
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adc->CTRLA.reg = ADC_CTRLA_PRESCALER_DIV32;
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// Select external AREFA as reference voltage.
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adc->REFCTRL.reg = ADC_REFCTRL_REFSEL_AREFA;
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// Set the reference voltage. Default: external AREFA.
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adc->REFCTRL.reg = adc_vref_table[self->vref];
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// Average: Accumulate samples and scale them down accordingly
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adc->AVGCTRL.reg = self->avg | ADC_AVGCTRL_ADJRES(self->avg);
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// Enable ADC and wait to be ready
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@ -38,9 +38,10 @@ typedef struct _dac_obj_t {
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mp_obj_base_t base;
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uint8_t id;
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mp_hal_pin_obj_t gpio_id;
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uint8_t vref;
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} dac_obj_t;
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STATIC const dac_obj_t dac_obj[] = {
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STATIC dac_obj_t dac_obj[] = {
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#if defined(MCU_SAMD21)
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{{&machine_dac_type}, 0, PIN_PA02},
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#elif defined(MCU_SAMD51)
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@ -51,25 +52,53 @@ STATIC const dac_obj_t dac_obj[] = {
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Dac *const dac_bases[] = DAC_INSTS;
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#if defined(MCU_SAMD21)
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#define MAX_DAC_VALUE (1023)
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#define MAX_DAC_VALUE (1023)
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#define DEFAULT_DAC_VREF (1)
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#define MAX_DAC_VREF (2)
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#elif defined(MCU_SAMD51)
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#define MAX_DAC_VALUE (4095)
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// According to Errata 2.9.2, VDDANA as ref value is not available. However it worked
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// in tests. So I keep the selection here but set the default to Aref, which is usually
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// connected at the Board to VDDANA
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static uint8_t dac_vref_table[] = {
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DAC_CTRLB_REFSEL_INTREF_Val, DAC_CTRLB_REFSEL_VDDANA_Val,
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DAC_CTRLB_REFSEL_VREFPU_Val, DAC_CTRLB_REFSEL_VREFPB_Val
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};
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#define MAX_DAC_VALUE (4095)
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#define DEFAULT_DAC_VREF (2)
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#define MAX_DAC_VREF (3)
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static bool dac_init = false;
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#endif
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STATIC mp_obj_t dac_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw,
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const mp_obj_t *args) {
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const mp_obj_t *all_args) {
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mp_arg_check_num(n_args, n_kw, 1, 1, true);
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uint8_t id = mp_obj_get_int(args[0]);
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const dac_obj_t *self = NULL;
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enum { ARG_id, ARG_vref };
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static const mp_arg_t allowed_args[] = {
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{ MP_QSTR_id, MP_ARG_REQUIRED | MP_ARG_INT, {.u_int = 0} },
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{ MP_QSTR_vref, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = DEFAULT_DAC_VREF} },
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};
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// Parse the arguments.
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mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
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mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
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uint8_t id = args[ARG_id].u_int;
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dac_obj_t *self = NULL;
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if (0 <= id && id <= MP_ARRAY_SIZE(dac_obj)) {
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self = &dac_obj[id];
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} else {
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mp_raise_ValueError(MP_ERROR_TEXT("invalid Pin for DAC"));
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}
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uint8_t vref = args[ARG_vref].u_int;
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if (0 <= vref && vref <= MAX_DAC_VREF) {
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self->vref = vref;
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}
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Dac *dac = dac_bases[0]; // Just one DAC
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// Init DAC
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@ -85,7 +114,7 @@ STATIC mp_obj_t dac_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_
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dac->CTRLA.bit.SWRST = 1;
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while (dac->CTRLA.bit.SWRST) {
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}
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dac->CTRLB.reg = DAC_CTRLB_EOEN | DAC_CTRLB_REFSEL(DAC_CTRLB_REFSEL_AVCC_Val);
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dac->CTRLB.reg = DAC_CTRLB_EOEN | DAC_CTRLB_REFSEL(self->vref);
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// Enable DAC and wait to be ready
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dac->CTRLA.bit.ENABLE = 1;
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while (dac->STATUS.bit.SYNCBUSY) {
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@ -95,21 +124,15 @@ STATIC mp_obj_t dac_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_
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// Configuration SAMD51
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// Enable APBD clocks and PCHCTRL clocks; GCLK3 at 8 MHz
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if (!dac_init) {
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dac_init = true;
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MCLK->APBDMASK.reg |= MCLK_APBDMASK_DAC;
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GCLK->PCHCTRL[DAC_GCLK_ID].reg = GCLK_PCHCTRL_GEN_GCLK3 | GCLK_PCHCTRL_CHEN;
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dac_init = true;
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MCLK->APBDMASK.reg |= MCLK_APBDMASK_DAC;
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GCLK->PCHCTRL[DAC_GCLK_ID].reg = GCLK_PCHCTRL_GEN_GCLK3 | GCLK_PCHCTRL_CHEN;
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// Reset DAC registers
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dac->CTRLA.bit.SWRST = 1;
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while (dac->CTRLA.bit.SWRST) {
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}
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dac->CTRLB.reg = DAC_CTRLB_REFSEL(DAC_CTRLB_REFSEL_VDDANA_Val);
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} else {
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dac->CTRLA.bit.ENABLE = 0;
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while (dac->SYNCBUSY.bit.ENABLE) {
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}
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// Reset DAC registers
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dac->CTRLA.bit.SWRST = 1;
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while (dac->CTRLA.bit.SWRST) {
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}
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dac->CTRLB.reg = DAC_CTRLB_REFSEL(dac_vref_table[self->vref]);
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dac->DACCTRL[self->id].reg = DAC_DACCTRL_ENABLE | DAC_DACCTRL_REFRESH(2) | DAC_DACCTRL_CCTRL_CC12M;
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// Enable DAC and wait to be ready
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@ -126,7 +149,7 @@ STATIC mp_obj_t dac_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_
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STATIC void dac_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
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dac_obj_t *self = self_in;
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mp_printf(print, "DAC(%u, Pin=%s)", self->id, pin_name(self->gpio_id));
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mp_printf(print, "DAC(%u, Pin=%s, vref=%d)", self->id, pin_name(self->gpio_id), self->vref);
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}
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STATIC mp_obj_t dac_write(mp_obj_t self_in, mp_obj_t value_in) {
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